Apparatus for drilling deviating bores utilizing a plurality of curved tubular drillguide sections



Feb. 16, 1954 .1. A. ZUBLIN APPARATUS FOR DRILLING DEVIATING BORES UTILIZING A PLURALITY OF CURVED TUBULAR DRILL GUIDE SECTIONS Filed NOV. 6, 1951 Mb I 1,, w. A H F u I 1 I 4 I I H 4 w x a 4 ATTORNEYS Patented Feb. 16, 1954 OFFICE.

APPARATUS FOR DRILLINGLDEVIATIN G BORES UTILIZING A PLURALITY OF CURVED TUBULAR. DRILL GUIDE SEC- TION S John A. Zublin, Los Angeles, Calif.

Application November 6, 1951, Serial No. 255,026

3 Claims.

The present invention relates to apparatus for drilling lateral bores which deviate from existing vertical well bores.

. According to the present invention the drill bitis carried at the lower end of the flexible drill string section and the short, curved drill guide sections are positioned above the bit. The as- :sembly can be lowered into the well with the curved drill guide sections in positions which cause them to impart reverse curvature to the flexible drill string section. The overall lateral dimensions of the apparatus are thus limited and no difficulty is encountered in lowering the assembly into an existing well bore. A whipstock is positioned within the existing well bore at the location at which it is desired for the lateral bore to deviate from the existing bore. This whipstock may be lowered into the well individually in advance of the drilling assembly or it may be lowered simultaneously therewith. The whipstock is provided with a curved guideway through which the curved drill guide sections pass. This curved guideway serves to initially force the drill bit laterally into the wall of the existing well bore to begin the drilling of the lateral bore. As the drilling proceeds the curved guideway of the whipstock causes the curved drill guide sections to assume relative positions which impart a substantially continuous curve to the flexible drill string section. The curved lateral bore which is thus drilled prevents the curved drill guide sections from relative rotation and the substantially continuous curve or" the flexible drill string section. is thus maintained during drilling. It will thus be seen that for practical purposes I obtain a rigid, continuously curved drill guide for. that part of the flexible drill string section which has passed through the whipstock. This advantageous result is obtained while still providing an assembly which can be easily lowered into the existing well bore.

Theprimary purpose of this invention is to provide a drilling assembly for lateral bores which can be easily and rapidly lowered into an existing well bore and which provides a rigid, continuously curved guide for the drill bit during drilling of the lateral bore. Another object of the invention is to limit the overall lateral dimensions of an assembly for drilling lateral bores during the lowering of that assembly into an existing well bore. Still another object of the invention is to provide a flexible drill string section and a rigid guide therefor in combination with a whipstock which is capable of controlling ioraltering the configuration of the rigid drill 2 guide at the point of deviation of the lateral bore in the well. Further objects and advantages of the invention will be understood by reference to the following description taken in connection with the accompanying drawing, wherein:

Figure 1 is a view partly in side elevation and partly in longitudinal section of an assembly which embodies the present invention and which is positioned in a well; and,

Figure 2 is a fragmentary view similar to Figure 1, but illustrating the apparatus in position for lowering into a well and prior to initiation of drilling of a lateral bore.

The reference numerals 3 and 4 designate tubular sections of a heavy duty flexible drill pipe of the type described and claimed in my Patent No. 2,515,366. The tubular section 4 is secured at its lower end by means of a dovetail tongue and slot connection 5 to a spindle 6 having a tubular passageway l therethrough. The shank 9 of the spindle 6 is received within the upper end of a short, rigid, tubular, curved drill guide section 9. The shank 8 is provided with antifriction ball bearings I0 and H to reduce the friction between this shank and the drill guide section 9. I also prefer to provide some suitable form of packing l2 to prevent leakage of drilling fluids.

A double-ended spindle 13 has its upper shank l4 journaled in the lower end of the drill guide section 9 and its lower shank I5 journaled in the upper end of a second tubular, curved, rigid drill guide section [6. The upper shank l4 may be provided with suitable ball bearings l1 and I8 and with a packing l9. The lower shank 16 may be similarly provided with anti-friction ball bearings 20 and 2| and with a packing 22.

l A bit spindle 23 is provided with a shank 24 which is journaled in the lower end of the drill guide section IS. The shank 24 is provided with suitable ball bearings 25 and 26 and with a suitable packing 21. A drill bit 28 is threadedly secured at 29 to the lower end of the spindle 23.

The ball bearings [0, H, H, I8, 20, 2|, 25 and 26 serve to reduce friction and also act as thrust bearings which prevent longitudinal separation of the elements with which the bearings are associated.

It will be noted that the construction of the tubular drill guide sections 9 and I6 is such that the spindles which are received within the upper and lower ends thereof must always lie atan angle to each other. When the drill guide sections 9 and I6 occupy the relative positions illustrated in Figure 2, a reverse curvature, as shown,

said metallic units, said drill guide sections when disposed in one relative position of rotation holding said flexible drill string section in a succession of reversed curves and when moved to another relative position of rotation holding said flexible drill string section in a substantially continuous curve and a whip-stock over which said curved drill guide sections may pass to insure their being brought from said first relative position of rotation to said latter relative position of rotation.

3. Apparatus for drilling a lateral bore deviating from an existing vertical well bore comprising a flexible, non-resilient drill string section, a drill bit secured to the lower end of and rotatable with said flexible drill string section, a plurality of relatively short independent rigid curved tubular drill guide sections mounted for independent rotation on said flexible drill string section, means on said flexible drill string section for holding said curved guide sections in spaced relation thereon, said drill guide sections when disposed in one relative position of rotation holding said flexible drill string section in a succession of reversed curves and when moved to another relative position of rotation holding said flexible drill string section in a substantially continuous curve and a whip-stock over which said curved drill guide sections may pass to insure their being brought from said first relative position of rotation to said latter relative position of rotation.

JOHN A. ZUBLIN.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Hall, Jr. Sept. 15, 1942 Hawn Mar. 21, 1950 Number 

